The present invention relates to a receiver or chucking device for the interchangeable attachment of a work-contacting probe pin or probe-pin combination to the probe head of a coordinate-measuring instrument. Such devices are intended to permit the fastest and easiest possible chucking of the probepin combination necessary for a specific measurement task.
Until now, it has been customary, in a manual operation, to screw or clamp the probe pin into the probe head. However, this manual operation is disadvantageous in the case of large-scale automatically controlled measurement processes, since it requires an operator whose sole purpose is to replace probe pins at relatively long intervals of time.
A measurement method is known from "American Machinist", October 1982, pages 152-153, in which the measurement machine itself changes the probe, under computer control. However, that reference does not show how to provide a chucking device for fastening the probe to the machine; in any event, this known automatic change method requires calibration of probe pins after each change, thereby slowing the measurement process.
British Patent No. 1,599,751 discloses a receiver for replaceable attachment of a complete probe head to the measuring spindle of a measurement machine. This receiver consists of a three-point support on the measurement spindle, and the feeler head is drawn against the three-point support by means of a clamping lever. The support unequivocally determines the position in space of the probe pins with a high degree of accuracy. But again, in the case of this instrument, replacement of probe heads is effected by an operator, who must actuate the clamping lever. There is also the disadvantage that, as a result of changing the complete probe head, a large number of different electrical connections to the measurement machine must be interrupted.
West German Gebrauchsmuster No. 7,400,071 discloses a probe head wherein a probe pin is removably secured to the probe head by means of several permanent magnets. Here, the magnet attachment serves to protect against collision damage. When the pin falls off, in the case of an excessive load, the pin must be reinserted by hand. This solution is not suitable for effecting an automatic change of the probe pin.